There is a significant need for a convenient, relatively easy assay for detecting the presence of phytase in animal feed. There is also a tremendous need for determining whether a plant has been genetically modified or whether grain or processed foods contain GMO traits. The need requires test methods that can detect and quantitate either the novel DNA or protein. The present inventions meet this need by providing monoclonal antibodies, hybridoma cell lines, immunological methods, reagents and kits for detection and quantification of phytase.